The present invention relates to frames for making photocopies.
More particularly, the present invention is concerned with frames for making photocopies from negatives, diapositives, etc. onto a photosensitive sheet material.
It is known in the prior art to provide a frame for making photocopies, including a support plate having a circumferential edge portion defining an upper surface which is adapted to support photosensitive sheet material. The upper surface of the frame may be subdivided into four equally large sections. Four covers are provided, for covering respective sections of the upper surface of the plate. Each cover is adapted to pivot independently of the others between a first position in which a respective section of the upper surface of the plate is uncovered and a second position in which the above-mentioned respective section of the upper surface of the plate is covered.
Thus, depending from the size of the photosensitive sheet material, different section of the upper surface of the plate may be exposed at once or one after another, for example, two halfes of the upper surface may be eposed at once or one after another, four quarters of the upper surface of the plate may be exposed at once or one after another. Correspondingly, the covers may be moved between the above-mentioned first and second positions at once as one unit or one after another. In order to avoid double illumination (i.e. exposure) which might occur due to mistake on the part of an operator, the covers overlap one another along their respective flanges, and therefore, the covers may be pivoted from the first into second position only in a certain succession which has to be reversely preserved when the covers move from the second into the first position. A given lightproof resistance of such a frame practically precludes any penetration of light onto the upper surface of the plate. However, sometimes such a light penetration is desirable, for example, when it is necessary to arrange a new negative, to adjust the focus, to read light filter--or exposure data.
Moreover, the overlapped flanges of the covers lead to development of white portions on the photocopies, corresponding to the unexposed portions of the photo sensitive sheet material during exposure of the latter. Later, these white portions have to be cut off from the made photocopies which obviously leads to undesirable waste of comparatively expensive material of the photocopies.
The above described frame may be used only for making photocopies of a photosensitive sheet material which has overall dimensions corresponding to those of the frame. Thus, different types of the photosensitive sheet material which is presently available on the market can not be used on such a frame without being correspondingly cut prior to installment onto the support plate. This consideration is for example fully applicable to the photosensitive sheet material having overall dimensions 18.times.24 em (i.e. 8.times.10")
In German utility model DGBM 7629374 it has been suggested, for eample, to use a frame having a support plate without circumferential flanges. Such a plate makes it possible to install on the upper surface thereof a photosensitive sheet material of different large sizes. In order to install a relatively small photosensitive sheet material, the plate may be correspondingly reversed so as to receive members confining the area corresponding to the actual size of the photosensitive sheet material. However, such a frame requires additional plates in order to ensure an adequate light sealing of the upper surface. In other words, this frame itself does not provide the adequate light protection for the upper surface of the plate.